AL Waterproofing System for Plywood Decks ICC ESR-2701
A-MAC is a combination of a metal lath reinforced and a fiber reinforced deck system for use on walking decks, balconies, corridors, stairs and landings with heavy traffic. It is regularly specified for hotels, condominiums, apartments, and office buildings. The AMAC is considered a super system and is specifically specified for extremely expansion and contraction or movement in the substrate.
The Life Deck A-MAC system incorporates Seal Guard under the lath as a back-up waterproof membrane and reinforcement for plywood seams. This product can be applied over most old deck systems to provide an excellent method for the rehabilitation of problem surfaces. It is bonded together with specially formulated acrylic emulsions and can be sealed with Life Deck 10 Series or 28 Series 100% Acrylic Top Coat. See Life Deck literature for types of finishes that can be achieved.
Plywood decks must be a single sheet of at least 3⁄4” CDX exterior grade. The deck should be tongue and groove when possible, properly blocked and nailed (glued & screwed is best). Plywood shall have a maxi- mum span of 16”. Slope must be a minimum of 1⁄4” per linear foot. Please refer to “Notice to Customer for Deck Coatings”. The decks should meet local building codes.
Surface should be clean, dry and free of grease, paint, oil, dust or any foreign material that may prevent proper adhesion.
Use a minimum of 26 gauge bonderized sheet metal. Flash at the junction of the wall and deck using 4” x 6” flashing. Flash the fascia with 2” x 4” flashing. Over- lap all seams at least 4”.
Caulk between overlapped flashing as well as the seam with a Life Deck approved sealant such as Rainbuster 500 or 900 or equivalent. Nail all flashing every 4”. Note: If the flashing is not bonderized, it must be etched in order for the coating to adhere properly.
One method of application is to roll out the membrane with the white side up and measure individual lengths with 2” minimum overlap. Pull the material tight from each end and remove the 2-1/2” strip of the overlap release film and adhere to the deck. Another method is to pull 12” to 24” of the release film and position the roll where desired.
Adhere the membrane firmly onto the deck. Begin pulling the release film in the opposite direction. The roll will follow as the release film is removed. Smooth the membrane as the adhesive back comes into contact with the deck. Install Life Deck Seal Guard over flashing. Since the material is not UV stable, the material is held back from the outside edge of the flashing and covered by the coating to be installed.
Place Life Deck metal lath (2.5 lbs per sq. yd. hot dipped galvanized) over the Seal Guard and cut it to fit the area. The lath should run across the grain of the plywood (across the long seams) when possible. The lath has a grain and it should be placed so that it curves down at the edge of the deck. The lath should be held back 1⁄2” from all edges.
This will allow the coating material to be feathered with a brush. With the lath in place, start in the center working your way out stapling the lath using 16 staples per square foot (minimum 1” crown x 5/8” long, 16 Ga. Non-corrosive Senco P10 or equal). Overlap the lath between 1” to 2” and staple every 1” to 2” along the seam. With a hammer, pound down any seams or staples that are higher than the lath.
Combine 1 bag of LD-1 cement into 1-1/4 gallons of LD-81 acrylic (4.5 gallon total) and add up to 1 quart of water. Mix until uniform with a jiffy mixer on a low rpm 1⁄2” drill motor. Pour the mixture (4.5 gallon total) onto the lath and trowel smooth at the rate of 40 square feet per batch.
Use a paintbrush to spread the base coat on the flashing making sure to get the mix- ture into seams and corners. Using a brush wet with water, feather all outside edges. As soon as it is dry, scrape off any high spots or ridges that may prevent a smooth slurry coat.
Sloping should always be done in the framing. It is the responsibility of the building owner and not the deck coating applicator. If sloping is requested it should be noted on the work order. The applicator along with the manufacturer should not be held responsible for the outcome of the remedial measure to help correct the preexisting slope condition.
Crickets (reverse slope to divert water to drain) may be installed and sloping may be done using an additional base coat (LD 81 Acrylic and LD 1 Cement). Maximum thickness should be 1⁄2” and should be applied 1⁄4” at a time. Additional lath my be installed prior to base coat to simulate a cricket.
Lay out the Life Deck Fiberlath reinforcing mesh on the deck overlapping the seams 1-2 inches. Trim to fit using a razor or knife. Apply the Life Deck 1589 Base Coat into the Fiberlath and laminate to the surface at the rate of 60 square feet per gallon. Using a razor knife cut any bubbles while still wet. Allow to dry 1-4 hours.
Combine one bag of LD-1 cement with four gallons of 1589 FM Base Resin (1 part LD-1 to 1 part 1589 by volume for smaller batches). Mix until uniform with a jiffy mixer on a low RPM 1⁄2” drill motor. Pour the mixture (5 gallon total) into the mesh and trowel smooth at the rate of approximately 256 square feet per batch.
Use a paint brush to spread the base coat on the flash- ing making sure to get the mixture into the seams and corners. Using a wet brush, feather all outside edges. Allow to dry (1-4 hours) and scrape off any high spots or ridges that may inhibit application of a smooth slurry coat. Trim any mesh that is showing. If you apply the Top Coat at this point the pattern of the fibermesh may show through.
Do not install “A-MAC” if the temperature is below 55 degrees. Rain could wash away Life Deck acrylic products if it occurs before final cure. If inclement weather threatens, cover the deck to protect the new application. Do not allow any Life Deck product to freeze. Store material at 40-110 degrees.
Most stains clean up with TSP and water. Use only a bristle scrub brush. The “A-MAC” System tex- tured deck should have annual inspections and be resealed with Life Deck top coat every 2 to 3 years depending upon ultraviolet exposure or sooner if recommended by your applicator.
Repairs may be done by grinding off the damaged area and replacing the material as written in this specification. Subsurface must be repaired if necessary and Fiberlath overlapped to integrate into the remaining surface.
Uncured material can be removed with water. If cured, material can only be removed mechanically or with solvents.